DES PLAINES, Ill. -- Officials say an aggressive swan may have contributed to the death of a suburban Chicago kayaker who drowned.

Anthony Hensley of Villa Park was pulled from a pond at a Des Plaines area condominium complex Saturday morning. The medical examiner's office ruled his death an accident.

Cook County sheriff's spokesman Frank Bilecki says the 37-year-old, an experienced kayaker, may have paddled too close to a nesting swan as he checked on the birds.

Bilecki says a jogger reported seeing Hensley fall from the kayak into the water. No one saw any swans attack him, but witnesses said they saw two birds circling him after he fell into the water. He went under as he attempted to swim to shore.